I upgraded from a no-name 20" to a Torker Unistar CX 24". I had to hack off about 2" from the seat stem so I could lower the seat and freemount easier. The new seat is also not very male-friendly and I now need to wear "core support" when I ride. Otherwise, the bigger wheel allows for me to cover distance a tad easier.

On the second or third day I had it, I went three miles, which was quite a workout!